Dropouts bending with torque arm?

[Jakeo1989]

I installed a 250w front hub motor a few weeks back and it works fine but I noticed the dropouts flexing slightly, so I installed Grin's V2 torque arm and that stopped it from bending any further for a few weeks but now it seems to be bending again. The rear part of the dropout fork seems fine but the front is bent outwards by two or three degrees. There are no visible cracks or fissures in the paint. It is somehow slightly worse on the side I installed the torque arm on (left). I re-installed the wheel and tried to straighten the dropouts but I was not strong enough to make a difference so I didn't push the issue. I also re-installed the torque arm and make sure there was no play in the direction the force is applied by the motor. Do I need to do anything else or should that stop anymore damage?

 

[vfr400]

What size torque arm did you use (12mm or 14mm slot), what motor did you fit and what voltage and current are you running with?

 

[Jakeo1989]

I'm not sure about the torque arm size (10mm I believe), but it fits the axle quite snugly. The motor is a 250w geared front hub motor sold by Cyclotricity and is 36v. The controller is rated at 7 amps (250w) continuous and has a peak of 14 amps (500w).

 

[peter.c]

I had the same problem on a trike with the cyclo kit the retaining washer that comes with the kit had lost its tab and did not sit flat so the nut pressure was uneven replaced the washer I ended up fitting torque arm to both sides no problems since

 

[vfr400]

There are two sizes for the slots in torque arms, 10 x 12 and 10 x14 mm. If you use the latter on a 10 x 12 axle, it'll distort and allow the axle to rotate. Both are a snug fit on the 10mm.

 

[Nealh]

Show us side view pic with motor and AR washers installed, are the washers tab fully engaging within the drop out ? From the pics which it looks like drop outs are unaltered and might also be that the ARW's aren't sitting in correctly.

 

[vfr400]

The tabs won't stop the drop-outs spreading. Instead, they'll contribute to it.